This invention is directed to a wave harvesting device which moves a first tube through a second tube. The second tube is concentric with and contains the first tube. A turbine is located in and moves in conjunction with the first tube through a liquid contained in the second tube. A float powered by waves on the surface of a body of water moves the first tube through the second tube to cause rotation of the turbine as it moves through the liquid.
Various wave harvesting devices have been proposed over the last century. These range from very simple devices to extremely complex integrated systems representing huge engineering projects. For the most part little practical application of these wave harvesting devices has been achieved for various reasons.
In a prior United States Patent, U.S. Pat. No. 4,462,211, I describe a wave harvesting device for use off shore. The device of this patent utilizes surface waves to raise and lower a float. The float in turn is connected to counter rotating turbines. The connection between the float and the turbines is of sufficient length to position the turbines in still water located at a depth below that influenced by the surface waves. While this device certainly is very utilitarian it must be used in water of sufficient depth to isolate the turbines from wave motion and thus requires mooring and tethering in water of such depth.
Various devices have been proposed for harvesting wave energy close to shore, either along the shoreline, in shallow water or tethered to a pier, oil rig or the like. A recent demonstration device utilizes the ocean's surge to drive an air turbine. While this type of device might find practicality in those shore areas wherein there are rocky cliffs immediately adjacent a surging surf, as for instance, adjacent the North Sea, this type of device finds little practicality in those areas of the world wherein the shoreline consists of sloping sandy beaches or wherein the prevailing wave heights are insufficient to drive an air turbine.
With the amount of energy available in the waves of the world's oceans and lakes and with the necessity of modern civilizations to wean themselves from polluting energy sources, such as oil and other fossil fuels, it is evident that there still exists a large potential use for practical devices capable of harvesting wave energy.